Our research program is broadly aimed at understanding the biochemistry and physiology of iron in an effort to improve iron nutrition in the human population: 1. Synthesis and nutritional evaluation of efficacious iron supplements for specific therapeutic and prophylactic applications: Newer forms of chelated and polymeric ferric iron offer distinct advantages over ferrous salts and conventional food iron additives for oral iron therapy and iron fortification of foodstuffs. We are investigating the nutritional and technological consequences of fortifying milk to develop a new vehicle for delivering supplemental iron and copper to anemic populations. 2. Establishing the mechanisms of gastrointestinal iron absorption and its regulation: We are examining the effects of dietary iron and body iron stores on the ability of the intestine to absorb and transport iron. We are reinvestigating the absorption of inorganic and prophyrin complexes of iron and cobalt to search for clues about the biochemistry of intestinal iron transport. 3. Understanding trace element interactions that influence iron utilization: We are investigating the crucial role of copper in the absorption, storage, and utilization of iron, in order to understand its biochemistry and to determine optimal levels of copper for distinct events in iron metabolism. 4. Understanding the mechanisms of iron storage and excretion: We are using the iron-chelating drug, desferrioxamine, as a tool to probe the tissue localization of excess iron and to determine the nature of the "chelatable iron pool" in order to potentiate the therapeutic value of chelators in the treatment of iron overload. 5. Development of potential tests of iron and copper assimilation in man: We are investigating the interrelationships of cobalt and iron metabolism in order to use cobalt as a "probe" for iron metabolism and absorption and to develop new tests for measuring the nutritional efficacy of trace elements in a variety of applications.